Gleanings in Materia Medica.
BY THE EDITOR.
Trehala which is used as food in Syria, has been investigated by Guibourt (1858), Berthelot and Hanbury. It is a cocoon formed upon a species of Echinops by a beetle which has been named Larinus nidificans, Guibourt, L. subrugosus, Chevrolat, and L. maculatus, Faldermann. The same substance has now been further examined by Dr. G. Apping (Thesis, Dorpat, 1885). His chemical analysis yielded moisture 10.78, ash 2.79, fat and chlorophyll 0.16, trehalose 23.84, tannin and citric acid traces; albuminoids soluble in water 8.09, soluble in soda 1.88, and insoluble in both liquids 2.31; cellulose like substance derived from starch 24.90; true starch 6.72; mucilage soluble in water 7.60, and mucilage insoluble in water 10.93. The most important constituents, trehalose, starch and mucilage, were fully examined, and inquiries were made into the origin of trehala. The cocoon is a product of the larva, but the material for this structure, although of vegetable origin, cannot have been derived from the plant, upon which it was built, since Apping found the pith and other portions of the tissue of the stems to be entirely free from starch and from trehalose, while the granules detected in portions gnawed by the larva were observed to be outside of the cell walls; these microscopic observations were verified by Professor Russow.
Products of Xanthorrhoea. Baron Ferd. von Mueller (Zeitschr. Oesterr. Apoth. Ver. 1885, 293) gives an account of the geographical distribution in Australia and Tasmania of the different species of this genus and of their resinous products, which of late years have been extensively exported by Messrs. William Somerville and Henry Willis who prefer the resin of X. hastilis, X. quadrangulata and X. Tateana for various reasons; X. Preissii yields one of the best resins, and is widely distributed in Western Australia. The resin of X. hastilis is known as gum acroides, is yellow and lighter colored than the other kinds, usually more sticky, and less inclined to become pulverulent; it is rather fragrant, but less so than the resin of X. quadrangulata. A comestible gum somewhat resembling tragacanth is sometimes deposited in the trunk in vertical concentric layers. 300 tons of the resins of X. hastilis have been exported in one year, and at one time the price rose to £65 per ton for the best quality, but for ordinary quality is from £7-10, One trunk yields on an average 5 pounds of resin which exudes from the persistent rudiments of the leaf bases, the exudation being sometimes increased by bush fires.
The resin of X. Tateana is dark reddish-brown, like the resin of X. australis, but dryer; a trunk yields about 20 pounds, and during the collection of the resin is destroyed; the value is about £25 per ton.
The author has sometimes seen masses of resin weighing 50 pounds at the base of the trunk of X. australis, most probably the produce of several years melted together by repeated fires. X. semiplana is stemless and produces little resin. X. minor is matted, the tufts of leaves being approximate and radical. In wet soil X. Preissii remains stemless.
The resin of X. quadrangulata is dark, glossy and of an agreeable odor resembling that of honey and benzoin; on exposure it becomes somewhat powdery, but is also found as small globular masses at the base of the trunk. X. arborea has the persistent bases of the leaves of previous years very short, and the resin is rather difficult to collect; the yield a of trunk is about 3 pounds, and the resin is almost ruby colored.